Apparatus for stenciling oval articles



y 1966 w. M. KARLYN ETAL 3,249,043

APPARATUS FOR STENCILING OVAL ARTICLES Filed Sept. 16, 1964 2 Sheets-Sheet 1 FIG. I

INVENTORS WILLIAM M. KARLYN DAVID AARON KARLYN ATTORN EYS y 1966 w. M. kARLYN ETAL 3,249,043

APPARATUS FOR STENGILING OVAL ARTICLES Filed Sept. 16, 1964 2 Sheets-Sheet 2 INVENTORS WILLIAM M. KARLYN DAVID AARON KARLYN WIME W ATTORNEYS United States Patent Mass.

Filed Sept. 16, 195A, Ser. N 396,953 3 Claims. (Cl. 161-38) This invention relates to apparatus for stenciling the peripheral surfaces of oval articles. The term oval article as used herein refers to an article having a surface to be stenciled which has the general cross-sectional form of an oval, with a varying curvature which is outwardly convex. The convex surface may be interrupted by flats or concave areas although the present apparatus is not suitable for stenciling these particular portions.

Circular cylindrical articles can generally be stenciled by rolling engagement with a stencil screen, without requiring any positive registration means for rotationally driving the article in synchronism with the relative translatory movement of the screen. The rolling friction is usually sufficient to rotate the article in good registration with the screen design, and Without slippage.

In dealing with articles having a varying radius of surface curvature, however, this is not the case, as the angular velocity of the article must be varied in inverse relation to the local radius of curvature in order to maintain a uniform linear velocity equal to the relative linear velocity of translation of the screen.

Means have previously been roposed by which some portion of the peripheral surface "of an oval article can :be successfully stenciled without smearing, but these have been limited to very moderate variations in radius of curvature, and have therefore not made it feasible to stencil any and all parts of the surface. For example, United States Patent No. 3,109,365 to William M. Ka-rlyn entitled Stenciling Apparatus, issued November 5, 1963, discloses and claims a fixture which rotates the article, in approximate synchronism with the translation of a screen, through a lost-motion connection between a crank arm afiixed to the screen frame and a rod carrying the article. The variation in angular velocity of the article brought about by this device tends to offset the variation in radius of curvature of the article to at least a limited extent, provided that the parts are properly proportioned. But only a rather small variation in the radius of the surface is permissible. In practice, a device of this kind can successfully label the portions of the oval which have a large and nearly uniform radius of curvature, but cannot pass the stencil around the more sharply curved parts.

It is the principal object of the present invention to provide an apparatus capable of stenciling any and all portions of the peripheral surface of an oval article, in registration and without smearing. It is a further object to provide a stenciling apparatus which completely compensates for the variation in radius of curvature of an oval article by maintaining an accurate inverse relationship of the angular velocity of the article. Further objects and advantages of the invention will appear as the following description proceeds.

Briefly stated, according to a preferred embodiment, we may carry out my invention by providing a movable carrier bearing a drive shaft, on which are mounted a chuck for rotatably supporting an oval article to be stenciled, and an oval gear for rotationally driving the article in synchronism with the linear velocity of a reciprocatory stenciling screen. As the article is rotated in pressure engagement with the screen, the movable carrier accommodates a transverse movement of the chuck corresponding to the varying radius of the article, so as to keep its surface in contact with the screen. Bias- 3,249,043 Patented May 3, 1966 ing means are provided to resiliently urge the carrier in a direction to maintain this surface engagement.

The oval gear is shaped to conform substantially to the surface outline of the particular style of article to be stenciled, and has a pitch oval of the same shape and dimensions as this surface. A rack is drivin'gly connected with the screen frame, and is shaped to conform to the path of reciprocatory motion of the screen, which will usually be rectilinear. The oval gear is meshed with the rack, and thus rotationally drives the chuck in synchronism with the movements of the screen; i.e., to impart a linear surface velocity to the rotating article which is equal to the linear velocity of the screen.

Preferably, an oval cam of the same shape as the outline of the article is also affixed to the drive shaft, and rolls against a guide plate which is carried by the screen frame and has the same shape as the rack. These means serve to maintain proper engagement between the oval gear and the rack at the pitch lines of these gears, so that the means used to bias the movable carrier will not mesh the gears too closely and produce premature wear.

The apparatus provides precise registration of the stencil design and the article, and is capable of accurate stencilin g of any or all portions of the peripheral surface of the article, no matter how great the variation in radius of curvature may be. It will be apparent, however, that this apparatus is not applicable to the stenciling of a flat surface; the oval surface to be stenciled must be convexly curved, although it may be interrupted by flat or concave portions if these are not to be stenciled by this apparatus.

While the specification concludes with claims particularly pointing out the subject matter which we regard as my invention, it is believed that a clearer understanding may be gained from the following detailed description of a preferred embodiment thereof, referring to the accompanying drawings, in which:

'FIG. 1 is a fragmentary sectional view in elevation of a preferred embodiment of the improved apparatus; and

FIGS. 2, 3, and 4 are fragmentary sectional views taken along lines 2-2, 3-3, and 4-'4, respectively, in FIG. 1.

The stenciling apparatus is organized upon a base cabinet 10, on which a framework including vertical standards 12, transverse braces 14, and longitudinal guide rods 16 is supported. The guide rods slidably support a screen frame for reciprocation in the directions shown by the arrows in FIG. 4. The frame is supported cantilever-fashion by a sliding assembly which includes a pair of slide bars 18 mounted reciprocab'ly on the guide rods 16, a base plate 20 connecting the slide bars, and spaced-apart cantilever arms 22 secured to one of the slide bars and to the upper surface of the screen frame (FIG. 1). Reciprocat-ory movement of the frame and its supporting assembly is obtained by means of a suitable double-acting pneumatic motor 24, mounted on the frame member 14 and having its piston rod 26 connected to the plate 20 of the sliding assembly by means of a bracket 28.

A rubber squeegee 30 is provided for pressure engagement with an upper surface of a silk screen 32, which is mounted in the frame 15 and bears any desired stencil design. By translating the screen and its supporting frame in either direction, after applying a pool of paint to the surface of the screen, a stencil pattern may be applied to the outer surface of an oval article, such "as the illustrated bottle 34. The squeegee is movably mounted so that it may be lifted from the screen after stenciling each article, 'by means of a yoke 36 of rectangular form. The

yoke is reciprocably mounted in a pair of bearing housings 38, which may contain ball bushings (not shown) for maintaining proper alignment of the squeegee. The housings are supported on the frame by means of a cantilevered bracket 40 and a framework comprising plates 42 and 44, and longitudinal braces 46. The piston rod 50 of a single-acting spring-return pneumatic motor 52 is secured to the yoke 36 for reciprocation of the squeegee to and from pressure engagement with the screen 32.

In order to maintain engagement of the variouslycurved surface of the article with the screen, it is necessary to support it both rotatably and for vertical movement. A carriage for the article is formed by a frame 50 having up-right standards 52, and a carrier 54 is pivotally supported upon a stationary axle 56 mounted in the standards. The carrier 54 includes a pair of parallel arms 58, for pivotally supporting a drive shaft 60; a bar 62 for maintaining alignment of the arms; and a third arm 64 for the support of one end of the stenciled article. The pivotal carrier is biased upwardly 'by means of a compression spring 66, disposed in a housing 68 which is pivotally mounted at 70 on the frame 50. The spring acts through a push rod 71 which is pivotally connected to the drive shaft 60 by a knuckle 72.

The bottle 34 is positioned on the axis established by the drive shaft 60, in a predetermined angular relation, by means of a chuck 74 conforming to the base of the article and pinned to the shaft. A conical inflation nozzle 76 enters into the mouth of the bottle to bring it into proper alignment with the drive shaft. The inflation nozzle is rotatably supported by a bearing unit 78 mounted in the arm 64, and is reciprocable along the rotational axis by means of a single-acting pneumatic motor 80 having a return spring 82. The arrangement is such that as compressed air is applied to the motor 80 through the conduit 84, a by-pass passage 86 formed through the nozzle 76 also supplies air to the interior of the bottle, which may be. of soft plastic and therefore too flexible for :proper stenciling without such inflation.

For rotationally driving the chuck and bottle in synchronism with the translation of the screen, an oval gear 90 is pinned to the shaft 60 in angular coincidence with the chuck. This gear is shaped to conform to the surface outline of the bottle, having its pitch oval of the same dimensions. The rack 92 meshes with the oval gear, and conforms in shape to the screens path of reciprocation. The screen is planar in the form shown, so that the rack is in this case of rectilinear extent. Driving connection is made between the screen frame and the rack, so that translation of the screen produces a synchronized rotation of the article with a varying angular velocity which is inversely proportional to the local radius of curvature of its surface. Consequently, the linear velocity of the bottle surface at its line of contact with the screen is "at all times equal to the linear velocity of the screen, and

precise registration is maintained, regardless of the degree of variation of surface curvature of the article.

In the preferred embodiment, provision is made for lowering the carriage from the screen for convenience in loading and unloading a series of articles; and in order to maintain the meshed engagement between the rack 92 and the gear 90, the driving connection between the rack and the screen frame 15 is made through a four-bar parallelogram linkage which is substantially as described and claimed in a co-pending United States patent application of William M. Karlyn Serial No. 341,968 filed February 3, 1964, and entitled Registering Mechanism for stenciling Apparatus. This linkage includes a pair of links 96, a drive bar 98, and the rack itself; these members being pivotally connected by pins 100. The drive bar is affixed to one of the slide bars 18 by means of a plate 102 and a spacer element 104. In any elev-at-ional position of the carriage, translation of the screen frame produces a corresponding translation of the rack and a synchronized rotation of the drive shaft. The carriage may be raised or lowered freely without losing the meshed engagement between the rack and the oval gear; it will be understood that the drive shaft will rot-ate to some extent while the carriage is moving vertically, but will resume the same relationship with the screen position each time it is raised to the stenciling position. Vertical displacement of the carriage is brought about by means of a suitable motor 106, whose piston rod 108 is connected to the carriage frame 50 by means of a yoke generally indicated at 110. Some angular movement of the pivotal carrier 54 will take place under the bias of the compression spring 66 as the carriage is raised or lowered, until the push rod 71 reaches the end of its stroke.

The preferred embodiment also includes an oval cam 112, which is mounted on the drive shaft 60' and cooperates with a guide plate 114 secured to the bottom of the plate 20. The cam conforms to the surface outline of the bottle and the pitch oval of the gear 90, while the track 114 is of the same form as the screen and rack, being of rectilinear extent in the illustrated embodiment. It will be understood from a comparison of FIGS. 2, 3, and 4 that since the oval gear 90, cam 112, and bottle 34 are angularly coincident on the drive shaft, a uniform pres sure engagement of the bottle against the screen, as well as uniform degree of mesh between the gear and rack, are maintained by this cam. It is feasible to eliminate the cam and permit the gear itself to serve this spacing function, but excessive meshing with the rack could result in rapid gear-tooth wear.

The operation of the apparatus will be readily apparent from the foregoing description. The opposite extreme positions shared in common by the oval gear, cam, and bottle, are shown in solid and dotted lines in FIGS. 2, 3, and 4, as well as the corresponding limits of pivotal movement of the carrier 54.

It will be understood from the foregoing description that the improved stenciling apparatus provides positive registration for stenciling the complete surface, or any portion of the surface, of oval articles, although their surface radius of curvature may vary very greatly. Designs in two or more colors may be stenciled by using successive screens in a well-known manner, and automatic re-registration is secured by the apparatus for this purpose as well. While we have illustrated and described a preferred embodiment of the invention by way of illustration, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the true spirit and scope of the invention, which we therefore intend to define in the appended claims without limitation to specific details of the foregoing embodiment.

What We claim is:

1. Apparatus for stenciling any portion of the convex peripheral surface of an oval article having a varying radius of surface curvature, said apparatus comprising, in combination; stenciling means including a frame adapted to support a stencil screen and mounted for reciprocation in a fixed path; motive means for driving said frame reciprocally; a carriage including a carrier mounted thereon for freedom of movement in a direction normal to the path of said frame; a drive shaft supported rotatably in said carrier for movement therewith; rotatable chuck means mounted on said drive shaft for supporting an oval article in a predetermined angular relation to said chuck means; means resiliently biasing said carrier toward said frame; a rack conforming to said fixed path of reciprocation and drivingly connected with said frame for movement therewith; a full oval gear whose pitch oval has a varying radius of curvature substantially conforming to the surface outline of an oval article to be stenciled, said gear being afiixed to said drive shaft in angular coincidence with said chuch means and being meshed with said rack for rotationally driving said drive shaft and said chuck means in synchronized response to reciprocation of said frame by said motive means, and to drive said carrier transversely to said fixed path of said frame to maintain uniform engagement between said article and a screen mounted in said frame as surface portions of said article of changing radius engage said screen; thereby to impart a linear surface velocity to an article supported in said chuck means which is equal to the linear velocity of said frame by rotating said article with an angular velocity which is inversely proportional to the varying local radius of curvature of said article.

2. Apparatus as recited in claim 1, together with a guide plate drivingly connected with said frame for reciprocation therewith and extending in parallel relation to said fixed path of reciprocation of said frame; and an oval cam whose active surface has a varying radius of curvature substantially conforming to the pitch oval of said gear, said cam being secured to said drive shaft in angular coincidence With said gear and said chuck means, and engaging said guide plate for controlling the move- 6 ment of said carrier transversely to said fixed path of said frame to maintain uniform mesh between said gear and said rack.

3. Apparatus as recited in claim 1, in which said carrier is pivotally mounted on said carriage on an axis parallel to and offset from said drive shaft for pivotal movement [about said axis of said gear, said chuck means, and an article supported therein, in unison.

References Cited by the Examiner UNITED STATES PATENTS 3,159,100 12/1964 Marquiss 10l40 3,180,252 4/ 1965 Fuerst 101-40 3,190,463 6/1965 Cohan 10138 X 7 ROBERT E. PULFREY, Primary Examiner.

WILLIAM MCCARTHY, Assistant Examiner. 

1. APPARATUS FOR STENCILLING ANY PORTION OF THE CONVEX PERIPHERAL SURFACE OF AN OVAL ARTICLE HAVING A VARYING RADIUS OF SURFACE CURVATURE, SAID APPARATUS COMPRISING, IN COMBINATION; STENCILLING MEANS INCLUDING A FRAME ADAPTED TO SUPPORT A STENCIL SCREEN AND MOUNTED FOR RECIPROCATION IN A FIXED PATH; MOTIVE MEANS FOR DRIVING SAID FRAME RECIPROCALLY; A CARRIAGE INCLUDING A CARRIER MOUNTED THEREON FOR FREEDOM OF MOVEMENT IN A DIRECTION NORMAL TO THE PATH OF SAID FRAME; A DRIVE SHAFT SUPPORTED ROTATABLY IN SAID CARRIER FOR MOVEMENT THEREWITH; ROTATABLE CHUCK MEANS MOUNTED ON SAID DRIVE SHAFT FOR SUPPORTING ON OVAL ARTICLE IN A PREDETERMINED ANGUALAR RELATION TO SAID CHUCK MEANS; MEANS RESILIENTLY BIASING SAID CARRIER TOWARD SAID FRAME; A RACK CONFORMING TO SAID FIXED PATH OF RECIPROCATION AND DRIVINGLY CONNECTED WITH SAID FRAME FOR MOVEMENT THEREWITH; A FULL OVERAL GEAR WHOSE PITCH OVAL HAS A VARYING RADIUS OF CURVATURE SUBSTANTIALLY CONFORMING TO THE SURFACE OUTLINE OF AN OVAL ARTICLE TO BE STENCILED, SAID GEAR BEING AFFIXED TO SAID DRIVE SHAFT IN ANGULAR COINCIDENCE WITH SAID CHURCH MEANS AND BEING MESHED WITH SAID RACK FOR ROTATIONALLY DRIVING SAID DRIVE SHAFT AND SAID CHUCK MEANS IN SYNCHRONIZED RESPONSE TO RECIPROCATION OF SAID FRAME BY SAID MOTIVE MEANS, AND TO DRIVE SAID CARRIER TRANSVERSELY TO SAID FIXED PATH OF SAID FRAME TO MAINTAIN UNIFORM ENAGAGEMENT BETWEEN SAID ARTICLE AND A SCREEN MOUNTED IN SAID FRAME AS SURFACE PORTIONS OF SAID ARTICLE OF CHANGING RADIUS ENGAGE SAID SCREEN; THEREBY TO IMPART A LINEAR SURFACE VELOCITY TO AN ARTICLE SUPPORTED IN SAID CHUCK MEANS WHICH IS EQUAL TO THE LINEAR VELOCITY OF SAID FRAME BY ROTATING SAID ARTICLE WITH AN ANGULAR VELOCITY WHICH IS INVERSELY PROPORTIONAL TO THE VARYING LOCAL RADIUS OF CURVATURE OF SAID ARTICLE. 